University of Minnesota Gophers football player Gary Tinsley died of an enlarged heart April 6, according to a Hennepin County Medical Examiner report released Wednesday.

Minneapolis Heart Institute researcher Dr. David Feldman told Tom Crann of All Things Considered that the condition could be caused by factors including genetic defects, drug use, infection or allergies. The examiner's report didn't find any drugs in Tinsley's system.

If it was genetic, Feldman said the condition could have manifest over a couple decades, but would probably have likely been picked up by an electrocardiogram, a common test for athletes performing at Tinsley's level.

But Tinsley also could have acquired the condition through an infection.

"He could have had a bad cold. which wound up attacking his heart and dying from something called myocarditis where he developed a large heart acutely related to, in some cases it could be a common cold," Feldman said. "Some of these develop over decades, some of them can literally develop over the course of weeks."

Tinsley, 22, started for the Gophers in every game for the last two seasons. The Jacksonville, Fla. native was scheduled to graduate this spring.